Inhibit subclassing native types with ABI3 set

src/types/mod.rs

@@ -103,6 +103,8 @@ macro_rules! pyobject_native_type_core {
 #[macro_export]
 macro_rules! pyobject_native_type_sized {
     ($name: ty, $layout: path $(,$type_param: ident)*) => {
+        // To prevent inheriting native types with ABI3
+        #[cfg(not(Py_LIMITED_API))]
         impl $crate::type_object::PySizedLayout<$name> for $layout {}
         impl<'a, $($type_param,)*> $crate::derive_utils::PyBaseTypeUtils for $name {
             type Dict = $crate::pyclass_slots::PyClassDummySlot;

tests/test_compile_error.rs

@@ -11,6 +11,9 @@ fn test_compile_errors() {
     t.compile_fail("tests/ui/reject_generics.rs");
     t.compile_fail("tests/ui/wrong_aspyref_lifetimes.rs");
 
+    #[cfg(Py_LIMITED_API)]
+    t.compile_fail("tests/ui/abi3_nativetype_inheritance.rs");
+
     tests_rust_1_43(&t);
     tests_rust_1_46(&t);
 

tests/test_inheritance.rs

@@ -3,7 +3,6 @@ use pyo3::py_run;
 
 use pyo3::types::IntoPyDict;
 
-use pyo3::types::{PyDict, PySet};
 mod common;
 
 #[pyclass(subclass)]
@@ -153,60 +152,63 @@ except Exception as e:
     );
 }
 
-#[pyclass(extends=PySet)]
-#[derive(Debug)]
-struct SetWithName {
-    #[pyo3(get(name))]
-    _name: &'static str,
-}
+// Subclassing builtin types is not allowed in the LIMITED API.
+#[cfg(not(Py_LIMITED_API))]
+mod inheriting_native_type {
+    use super::*;
+    use pyo3::types::{PyDict, PySet};
 
-#[pymethods]
-impl SetWithName {
-    #[new]
-    fn new() -> Self {
-        SetWithName { _name: "Hello :)" }
+    #[pyclass(extends=PySet)]
+    #[derive(Debug)]
+    struct SetWithName {
+        #[pyo3(get(name))]
+        _name: &'static str,
+    }
+
+    #[pymethods]
+    impl SetWithName {
+        #[new]
+        fn new() -> Self {
+            SetWithName { _name: "Hello :)" }
+        }
+    }
+
+    #[test]
+    fn inherit_set() {
+        let gil = Python::acquire_gil();
+        let py = gil.python();
+        let set_sub = pyo3::PyCell::new(py, SetWithName::new()).unwrap();
+        py_run!(
+            py,
+            set_sub,
+            r#"set_sub.add(10); assert list(set_sub) == [10]; assert set_sub._name == "Hello :)""#
+        );
+    }
+
+    #[pyclass(extends=PyDict)]
+    #[derive(Debug)]
+    struct DictWithName {
+        #[pyo3(get(name))]
+        _name: &'static str,
+    }
+
+    #[pymethods]
+    impl DictWithName {
+        #[new]
+        fn new() -> Self {
+            DictWithName { _name: "Hello :)" }
+        }
+    }
+
+    #[test]
+    fn inherit_dict() {
+        let gil = Python::acquire_gil();
+        let py = gil.python();
+        let dict_sub = pyo3::PyCell::new(py, DictWithName::new()).unwrap();
+        py_run!(
+            py,
+            dict_sub,
+            r#"dict_sub[0] = 1; assert dict_sub[0] == 1; assert dict_sub._name == "Hello :)""#
+        );
     }
 }
-
-// Subclassing builtin types is not allowed in the LIMITED API.
-#[test]
-#[cfg_attr(Py_LIMITED_API, should_panic)]
-fn inherit_set() {
-    let gil = Python::acquire_gil();
-    let py = gil.python();
-    let set_sub = pyo3::PyCell::new(py, SetWithName::new()).unwrap();
-    py_run!(
-        py,
-        set_sub,
-        r#"set_sub.add(10); assert list(set_sub) == [10]; assert set_sub._name == "Hello :)""#
-    );
-}
-
-#[pyclass(extends=PyDict)]
-#[derive(Debug)]
-struct DictWithName {
-    #[pyo3(get(name))]
-    _name: &'static str,
-}
-
-#[pymethods]
-impl DictWithName {
-    #[new]
-    fn new() -> Self {
-        DictWithName { _name: "Hello :)" }
-    }
-}
-
-// Subclassing builtin types is not allowed in the LIMITED API.
-#[test]
-#[cfg_attr(Py_LIMITED_API, should_panic)]
-fn inherit_dict() {
-    let gil = Python::acquire_gil();
-    let py = gil.python();
-    let dict_sub = pyo3::PyCell::new(py, DictWithName::new()).unwrap();
-    py_run!(
-        py,
-        dict_sub,
-        r#"dict_sub[0] = 1; assert dict_sub[0] == 1; assert dict_sub._name == "Hello :)""#
-    );
-}

tests/ui/abi3_nativetype_inheritance.rs

@@ -0,0 +1,7 @@
+use pyo3::prelude::*;
+use pyo3::types::PyDict;
+
+#[pyclass(extends=PyDict)]
+struct TestClass {}
+
+fn main() {}

tests/ui/abi3_nativetype_inheritance.stderr

@@ -0,0 +1,13 @@
+error[E0277]: the trait bound `pyo3::ffi::dictobject::PyDictObject: pyo3::type_object::PySizedLayout<pyo3::types::dict::PyDict>` is not satisfied
+  --> $DIR/abi3_nativetype_inheritance.rs:4:1
+   |
+4  | #[pyclass(extends=PyDict)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `pyo3::type_object::PySizedLayout<pyo3::types::dict::PyDict>` is not implemented for `pyo3::ffi::dictobject::PyDictObject`
+   |
+  ::: $WORKSPACE/src/type_object.rs:96:22
+   |
+96 |     type BaseLayout: PySizedLayout<Self::BaseType>;
+   |                      ----------------------------- required by this bound in `pyo3::type_object::PyTypeInfo`
+   |
+   = note: required because of the requirements on the impl of `pyo3::type_object::PySizedLayout<pyo3::types::dict::PyDict>` for `pyo3::pycell::PyCellBase<pyo3::types::dict::PyDict>`
+   = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)